Based on the percentages of my multi year JFK flights...

domestic arrival - sit on the left (A seat). If you fly direct LGA, your flight will fly high over Manhattan going from the north to the south. As the flight decends, it may loop around New Jersey and head to JFK. Also, it's possible that you will have Canarsie approach. That will provide a (limited) view of Manhattan and Brooklyn.

domestic departure - Based on the percentages, sit on the right side of the plane. Sometimes we take off to the west (right side), then loop around to the north. If this happens, you'll see manhattan from the left side at a much higher altitude.

foreign arrivals may land from the east. If so, the right side will barely reveal Manhattan in the very far off distance.

foreign departures - your call